The present invention is directed to the utilization of earth or rock or mineral drilling bits which are power driven in rotation. In many applications, deep holes are drilled in circumstances where there is not enough clearance in the working area to accommodate the use of a long drill shank. In addition, replaceable bits are used. Under these circumstances, it has been common to provide a series of drill steels which can be joined together as the depth of the hole increases. These drill steels may consist of a starter driver bar having a lower end to connect to the motor or power drive and an upper end to receive a bit. This assembly is used to drill to a certain depth. Then the starter bar is removed and a lead extension is connected to the driver and the bit. Subsequently, a middle extension is used and extensions are used until the hole has reached the desired depth. The composite extensions are called a drill string.
U.S. Pat. No. 4,009,760 to Hansen and Smarrella issued Mar. 1, 1977 has a disclosure pertinent to this art. The U.S. Pat. No. 3,519,091 to Leibee and Oaks, issued July 7, 1970, is also pertinent to the general field of drilling.
Some of the drilling in underground areas is called roof drilling wherein holes are drilled in the roof of the cavity and roof bolts are driven or installed into these holes to reinforce the upper area of the cavity to prevent collapse.
There are number of different starter drill steels and also a number of different manufacturers of power units which drive the steels in the course of the drilling. These power units have different external socket shapes ranging from axially narrow gear teeth to long gear teeth, axially extending splines and axial grooves, and wide spaced splines. Each will fit a power driver of a particular manufacturer.
In addition, there are a number of different shapes for drill steels including those with a square or hexagonal driver with round or hexagonal intermediate portions at different axial locations.
It is an object of the present invention to provide a drive chuck which can have an external shape to fit respective power drives of different manufacturers and also have an internal shape to fit a variety of different ends on bit carrying steels as well as roof bolt nuts. The use of a drive chuck of this nature reduces the inventory needed at a mine site and allows the use of drill steels of a variety of manufacturers.
Other objects and features of the invention will be apparent in the following description and claims in which the principles of the invention are set forth together with details to enable persons skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.